Resumo (PT):
Abstract (EN):
The Sea-wave Slot-cone Generator (SSG) is a multi-level overtopping based wave energy converter that
can be installed either nearshore or offshore. The installation in harbor breakwaters and in the shoreline
presents several advantages despite the usual exposure to smaller waves than at offshore locations. This
work analyzes the effect of wave focusing walls (i.e., wave concentrators) on the performance of isolated
SSG units using a physical model built on a geometric scale of 1/40. Seven configurations were defined by
changing the opening angle and the crest level of those elements. The use of wave concentrators proved
to be advantageous since a wider wave front is captured and the run-up and overtopping phenomena are
enhanced on the SSG ramp owing to the wave energy concentration (walls tapering effect). In fact, the
total mean power captured increased for all SSG configurations with concentrators in comparison to
the base configuration (without concentrators), regardless of the sea state considered. In terms of hydraulic performance, the gain associated to the use of wave concentrators depends on the characteristics of
incident waves, being higher for the smaller significant wave heights and the shorter peak wave periods.
The hydraulic efficiency, defined as the ratio between the total mean power captured per meter of SSG
width and the wave power per meter width of the incident waves, increases with the significant wave
height and reduces with the peak wave period in all tested SSG configurations. In addition, in comparison
to the base configuration, the hydraulic efficiencies with concentrators were higher for the smaller significant wave heights, but smaller for the other sea conditions. The use of wave concentrators increased
the annual energy production approximately to the double. Overall, the application of the SSG technology
in breakwaters presents itself as promising considering the characteristics of the wave resource
nearshore or even in onshore locations.
Language:
English
Type (Professor's evaluation):
Scientific
Contact:
fpinto@fe.up.pt; pjrsantos@fe.up.pt
No. of pages:
11